Flight guidance system providing perspective flight guidance symbology

Abstract

A flight guidance system providing perspective flight guidance symbology using positioning and terrain information provides increased pilot situational awareness of an aircraft. The guidance system uses a positioning system and a detailed mapping system to provide a perspective display for use in an aircraft. A Perspective Flight Guidance (PFG) symbology set is thereby displayed on a pilot display. The PFG symbology set includes broken line symbols representing an open tunnel and providing flow field data, a half-bracket symbol to indicate that the aircraft is no longer in the open tunnel represented by the broken line symbols and a quickened flight path vector (QFPV) symbol to provide the pilot with predictive flight path information.

Description

FIELD OF THE INVENTIONThe present invention relates generally to aircraft guidance systems, and more particularly to terrain following / terrain avoidance systems using perspective flight guidance information.BACKGROUND OF THE INVENTIONIn order to reduce tracking errors and pilot workload, a pilot may be provided with increased situational awareness of an aircraft with respect to a desired flight path. In particular, a pilot must be aware of the actual aircraft performance, or flight path vector (FPV), the desired or commanded aircraft performance, and the predicted aircraft performance. The use of a perspective display with a predictive flight path or performance symbology set provides increased situational awareness. Perspective displays with predictive symbology permit a pilot to “see” what will be required or demanded of the aircraft to maintain a desired flight path, as well as where the aircraft will be in a finite period of time. With the increased situational awareness, the pi...

AI Technical Summary

Benefits of technology

In particular, a guidance system of the present invention attempts to prevent inadvertent flight into terrain and allows terrain-hugging flight to limit intervisibility using terrain elevation data contained within, for example, a digital map system, updated aircraft inertial track data from flight guidance computers and differential global positioning system (dGPS) navigation systems. This information is used in combination with generated perspective flight guidance symbology to enable a pilot to view visual representations of upcoming and lateral terrain.

The system provides a Perspective Flight Guidance (PFG) display that, in one embodiment, utilizes dGPS for waypoint geolocation, combined with a “quickened” predictive FPV symbol and “tunnel-in-the-sky” pathway guidance. The display enables pilots to anticipate avoidance flight requirements, thereby permitting the pilots to fly low to the ground (i.e., terrain flight) while avoiding obstacles (i.e., terrain avoidance) with increased accuracy, reduced intervisibility and reduced workload.

Problems solved by technology

Further, current generations of terrain flight guidance systems use radiated emissions and track errors displayed using compensatory tracking symbology (e.g., Delta-Veebar and Two-bar).

Such systems operate satisfactorily, but are limited in their ability to display future flight path information to the pilot and / or the results of pilot control input.

Thus, such displays cause much “mental gymnastics”, cognitive processing, and pilot mental workload, which may lead to additional error.

However, compensatory tracking symbology does not provide the pilot with information indicating how far the aircraft is off course or what flight control input is required to regain course centerline.

Furthermore, compensatory tracking does not provide flight path predictability, and displays that utilize compensatory symbology typically require more cognitive processing by the pilot.

This causes heavy pilot mental workload that may lead to errors, especially in high workload constrained terminal areas or during low altitude operations.

For example, excessive pilot mental workload can lead to full-scale deflection errors or total loss of situational awareness resulting in a maximum deviation mandated missed approach.

Thus, compensatory symbology often creates display clutter and high pilot cognitive workload, which increases the risk of flight technical errors (FTE's).

These systems, while accurate, are limited in that the display and data are restricted by the performance of the sensor system.

For example, turning limitations from the turn rate / bank angle limiter on some multi-mode radars precludes the system from “seeing” around or into the turn.

Further, and for example, current sensor-based systems cannot provide the pilot with reliable “nose over” cueing to enable terrain flight because the emitter sensor cannot “look over” the terrain ahead, but must rely on line-of-sight (LOS) operation.

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